Topband: Top-band Prop along grayline?
K1ZM@aol.com
K1ZM at aol.com
Fri Mar 11 06:57:31 EST 2005
Hi Tony
I saw your post and even without being able to visualize the actual grayline
at 2200z on say 01 January, I can add this to the mix:
1) Some of us who are more fortunate have directional lowband antennas (well,
relatively so) and in this case I am talking about our TX antennas - NOT
beverages for RX. Although my friend Bob Brown, NM7M, once called my 160M
4-square array a "crude instrument" (and he is partially correct!), it does allow me
to recognize from which "relative direction" at least signals are arriving at
my NY and Cape Cod, MA locations.
2) While not a perfect instrument by any means, I am able to tell instantly
the following:
a) Whether it is a short-path event to JA (meaning the more normal 330 degree
heading - or perhaps a West/SW skewing of the short path to 300/270 or even
to as much as 240 degrees under exteme skewing)
or
b) Whether the JA's are arriving coming over EUROPEAN routing at 30-70
degrees, for example
or
c) Whether the arrival routing to the NORTHEAST part of the USA is coming
from a Southeast heading - meaning a routing over ZD8, Southern Africa and then
back up the Indian Ocean somehow, across the Pacific and eventually up to JA.
(Please see next qualifying paragraph!)
I have NEVER known for SURE (admittedly) whether this was the true sequence
of pathing at 2145z to JA - or - whether instead the signals keep going SOUTH
over the SOUTH pole from New England and then up to JA on the backside.
The true routing MUST follow at least a semi-darkness path to work reliably -
that much we know! The fact that it is SO VERY DEPENDENT on a quiet solar
and auroral zone might suggest that it is INDEED OVER THE SOUTH POLE.
And, while the path out over Africa, over the Indian Ocean, then across the
Pacific up to JA is in darkness along the entire route at 2200z, I really
cannot tell at all if that is what is really happening.
BUT - WHETHER THE SIGS go the AFRICAN routing
OR
WHETHER THEY GO over the SOUTH POLE and then up the backside (which seems a
SHORTER path to me by the way) - I do know with ABSOLUTE CERTAINTY that I must
aim my XMIT antenna between a 135-150 degree azimuth (meaning SE from Cape
Cod) to work JA, HL, YB, 9V1, VR2, HS, XW, 3W, etc etc during the short
(long-path (skewpath?) opening which occurs from about 2140-2200z to JA and extends to
around 2315 for 9V, for example, which is local sunrise time in Singapore.
This is a completely DIFFERENT path entirely than working into VU at 0115z
from the EAST coast on 160M - which is clearly a NE pathing event at about 35-40
degrees from W1, for example.
So, I am not sure if I have helped you much EXCEPT to note that the routing
from New England is definitely SE at sunset from W1-W3 (and it is exactly the
same on 3.5Mhz).
It is rare for W4 to make it LP into JA on this path (even on 80M) because of
the lack of overlapping darkness on the W4 side here in the states. I do
think on some of the more EXCEPTIONAL days that guys like W3LPL and perhaps even
W4MYA/W4DR have made a JA L/P on 75/80m but these occurrences are quite rare
to say the least.
Hope this helps a bit Tony.
73 JEFF
K1ZM at aol.com
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